Oil tankers and cargo ships line up in the Strait of Hormuz as seen from Khor Fakkan, United Arab Emirates. AP
The closure comes less than 24 hours after Tehran agreed to a two-week ceasefire with Washington aimed at ending more than 40 days of the US-Israeli war on the country and allowing maritime traffic to resume through the Strait of Hormuz.
Iranian authorities said tanker traffic had now been halted, with Fars news agency reporting that two oil tankers had passed earlier on Wednesday with the Iranian Revolutionary Guard Council's (IRGC) permission before movements were stopped.
Tehran said it would offer safe passage in coordination with its armed forces, but warned that any vessel attempting to transit without approval would be “targeted and destroyed”.
Any closure "is completely unacceptable," White House Press Secretary Caroline Leavitt told reporters.
"I will reiterate the president's expectation and demand that the Strait of Hormuz is reopened immediately, quickly, and safely."
Tehran's decision, carried by Iranian news agencies, came as Israel launched massive strikes on residential buildings in Beirut and across Lebanon on Wednesday, killing more than 112 people and wounding at least 873, according to initial reports.
During the day, Trump and Netanyahu claimed that Lebanon was not included in the ceasefire agreement with Iran.
The Israeli strikes on Lebanon and the reported Iranian halt to shipping through Hormuz cast doubt on the truce's durability.
Despite the American and Israeli claims, in an interview with CNN, the Pakistani ambassador to the United States confirmed that "based on understandings reached at the highest levels of government," Lebanon was included in the ceasefire agreement brokered between the United States and Iran.
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